1. Field of the Invention
This invention relates to C7 gene, a novel gene induced in response to injury stress, osmotic-pressure stress, salt stress or low-temperature stress, which encodes a receptor-like protein.
2. Description of the Art
In the future, technical development for efficient production of crops in agriculture will be required, because food crisis is expected to occur. Since loss of food production caused by various environmental stresses is a serious problem in the field of agriculture, there is great demand on production of a plant exhibiting tolerance to various environmental stresses.
To attain such a purpose, it is indispensable to investigate on self-defense system against stresses in a plant. The self-defense system can be roughly classified to the following three stages: (1) recognition of stress; (2) transduction of stress signal; and (3) response to stress. The investigation on the second process of signal transduction and third process response have achieved some progression and factors involved in the processes were identified. However, the knowledge on the first recognition process and the relation of the process with the signal transduction process remains to be insufficient. In general, it is known that an upstream factor operates to control plural downstream factors in the signal transduction pathway. Therefore, it is considered that the analysis on the recognition process, which exists in the upstream of the pathway, might give a method for efficient and concurrent control of plural factors, at the transduction pathway or the recognition pathway locating downstream of the stress defense mechanism.
Therefore, the inventors investigated on a method to render stress resistance to a plant, using factors operating in the process of stress recognition in a plant. That is, the object of this invention is isolation of a gene involved in early stage of stress response and analysis of the mechanism of the function of the gene.
The inventors searched for a gene induced by exposure to stresses, those are injury stress, osmotic-pressure stress, salt stress and low-temperature stress (4xc2x0 C.), using tobacco (Nicotiana tabacum cv Xanthi nc). As the result, the inventors obtained C7 gene temporarily induced by those stresses in its early stage. That is, C7 gene of this invention was initially identified by FDD method as a rapidly and transiently induced clone upon wounding. Using this FDD fragment, the full-length cDNA clone was isolated from a cDNA phage library prepared from wounded tobacco plants. From the viewpoint of the expressive response of C7 gene, it is assumed that the product of said gene may be a sensor which recognizes external stress and involved in expression control of stress responsive gene existing its downstream. Therefore, it is expected that, a plant exhibiting resistance to injury stress, osmotic-pressure stress, salt stress or low-temperature stress might be produced by incorporating said gene into a plant.